Hydraulic jar



D. D. WEBB HYDRAULIC JAR Oct. 24, 1961 3 Sheets-Sheet 1 Filed July 27,1959 ATTORNEY D. D. WEBB HYDRAULIC JAR Oct. 24, 1961 3 Sheets-Sheet 2Filed July 27, 1959 INVENTOR ATTORNEY Oct. 24, 1961 D. D. WEBB 3,005,505

HYDRAULIC JAR Filed July 27, 1959 5 Sheets-Sheet 3 J. @zw- 9- 10' IIE, eu n IIIN,

INVENTOR 25e/ea D. #V555 ATTORNEY 3,005,505 HYDRAULIC JAR Derrel D.Webb, Houston, Tex., assigner to Houston Engineers, Inc., Houston, Tex.,a corporation of Texas Filed July 27, 1959, Ser. No. 829,658

8 Claims. (Cl. 175-297) Ihis invention relates to well apparatus andmore particularly to a hydraulic jar designed to impart an impact towell tools or other objects lodged in a well bore for the purpose ofremoving the same. provement over `that shown in Patent No. 2,802,703,to Harry W. Harrison, issued August 13, 1957.

As is well known, 'broken drills, broken sections of pipe and otherobjects occasionally become lodged in the bore of a well during drillingoperations and when this occurs, drilling operations must be suspendeduntil the objects have been removed. This often requires long andtedious fishing operations and in order to facilitate the removal ofsuch objects, it has heretofore been proposed to utilize various typesof jarring mechanisms to impart an impact to the object lodged in thewell bore in order to free the same and such jarring mechanisms havealso included those of the so-called hydraulic type in which a fluid isutilized to facilitate building up a force or tension in Ya pipe stringor the like, which when released, imparts an upward impact to theobjects lodged in the well bore in order to free the same. v

Many of the prior art hydraulic jar mechanisms are exceedingly complexrequiring a relatively large number of parts which not only materiallyincreases the cost of such devices, but also renders the same subject tofrequent failure, thereby further increasing the cost of well drillingoperations, but in the case of many of these prior art hydraulic jarmechanisms, the desired result was not obtained by reason of the factthat such mechanisms not only delivered an upward impact to the objectlodged in the well, but in resetting the mechanism for delivering afurther impact, an impact was also delivered in the downward directionwhich often resulted in more rmly lodging the objects in the well bore.In other words, these prior art hydraulic jar mechanisms deliver animpact in both upward and downward directions, whereas the only eiectiveimpact is in an upward direction and the downward impact is not onlyunnecessary and wasteful, but is also a distinct disadvantage in thatthe same may defeat the very purpose of utilizing the jarring mechanism.

It is accordingly an object of the present invention to provide ahydraulic jar designed to deliver an impact only in one direction.

A further object of the invention is the provision of States Patent Theinvention is an ima hydraulic jar which is relatively simple inconstruction embodying only three relatively movable parts therebyreducing the cost of manufacture and providing a longwearing dependabledevice.

A still further object of the invention is the provision of a hydraulicjar designed to deliver an impact in one direction only and which may berapidly reset for delivering a further impact, such resetting operationbeing entirely free of impact in the opposite direction to thatYdesired.

Another object of the invention is the provision ofa hydraulic jarutilizing a closed fluid chamber and a fluid of low viscosity, such asmotor oil.

A further object of the invention is the provision of a hydraulic jarprovided with a closed uid chamber in ICC of a hydraulic jar providedwith a closed fluid chamber in which a piston recprocates, the pistonbeing provided with a metallic cup washer of a relatively soft material,such Washer providing a seal lbetween the portions of the fluid chamberabove and below the piston there being also provision for convenientlyremoving and replacing the cup washer in the event of Wear or damagethereto.

Another object of the invention is the provision of a hydraulic jarhaving slidable and non-rotatably interrelated parts which permitsapplying a torque through the jar mechanism to the fishing tool or otherobject to which the jar is attached.

Further objects and advantages of the invention will be apparent fromthe following description taken in conjunction with the accompanyingdrawings wherein:

FIG. la is a longitudinal sectional View showing the upper portion of ahydraulic jar constructed in accordance with this invention;

FIG. lb is a longitudinal sectional view showing the intermediateportion of the hydraulic jar shown in FIG. 1a;

FIG. lc is a longitudinal sectional view showing the lower portion ofthe hydraulic jar of this invention;

FIG. 2 is a longitudinal sectional view to an enlarged scale showing theconstruction of the piston, as well as the relationship between thepiston and the sleeve slidable in the fluid chamber;

FIG. 3 is a side elevational view of the sleeve which is slidable in thefluid chamber;

FIG. 4 is a sectional view taken on the line 4 4 of FIG. 3 and showingthe inwardly projecting ange in the lower end 'of the sleeve of FIG. 3;

FIG. 5 is a sectional view taken on the line 5 5 of FIG. la and showingthe structure which permits the application of torque through thehydraulic jar of this invention;

FIG. 6 is a sectional view taken substantially on the line 6-6 of FIG.lb and showing the relationship between the intermediate body portionconstituting the uid charn-l ber, the sleeve slidable in the chamber andthe piston slidable in the sleeve and chamber;

FIGS. 7 to l0 are fragmentary diagrammatic views in section showing theoperation of the hydraulic jar of this invention during delivery of animpact; and

FIGS. ll to 14 are fragmentary diagrammatic views in section showing therelationship of the various parts during resetting of the tool fordelivery of a further impact.

With continued reference to the drawings, there is shown a hydraulic jarconstructed in accordancewith this invention and which may well comprisean elongated hollow upper body portion 10 to the lower end of which issecured by screw threads or other suitable fastening means 11, aconnecting member 12. Secured to the lower end of the connector member12 by screw threads or other suitable means 13 is an intermediateelongated hollow body portion 14 and as best seen in FIG. 1b, theintermediate portion 14 is provided adjacent the upper end thereof withan inwardly projecting flange 15 which serves to receive and engagepacking rings or washers 16 which in turn are engaged by the lower end'17 of the connecting member 12 thereby providing a fluid tight which apiston reciprocates, a metallic cup washer being cup washer.

A still further objectof the invention is the provision --L seal betweenthe connecting member 12 and the interior of the intermediate bodyportion 14. The'packing rings or Washers 16 also perform anotherfunction which will be later described. Secured tothe lower end of theinteri mediate body portion 14 by screw threads or other suit-v ablemeans 18 is a lower elongated hollow body portion 1'9 and in order toprovide a fluid tight connection between the lower body portion 19 andthe intermediate body portion 14, a sealing ring 20 may be seated in anannular, groove 21 to engage the lower end of the inten mediate bodyportion 14 to provide such seal. As shown in FIG. 1c, the lower end ofthe lower body portion 19 is connected by screw threads or the like 22,to a coupling member 23 provided on the lower end thereof with pipethreads 24 for connecting the coupling member 23 and the remainder ofthe hydraulic jar to a fishing tool or other object to which the samemay be attached.

A reduced portion 25 in the'upper end of the upper body portion 1Gprovides a downwardly facing impact receiving shoulder 26 and as shownin FIG. 5, the reduced portion 25 is provided with a non-circular bore27 having opposed flat surfaces 28 therein, the purpose of which will bepresently described.

Slidably received in the bore 27 is an elongated mandrel 29 havingopposed iiat surfaces 30 engaging the tlat surfaces 28 on the reducedportion 25 and consequently, the mandrel 29 is freely slidable in thebore 27 but is nonrotatable therein due to the inter-engagement of theflat surfaces 28 and 3ft. At the upper end of the mandrel 29 an enlargedportion 31 is provided with a female type thread 32 Ifor permittingconvenient coupling of the hydraulic jar of this invention to the lowerend of a drill string or the like. The mandrel 29 terminates within theupper body portion 1G and the lower end of the mandrel 29 is secured byscrew threads or the like 33, to a hammer member 34 movable within theupper body portion with the mandrel 29. The upper end 35 of the hammerImember 34 provides an impact surface for engaging the impact shoulder26 on the upper body portion 10 in a manner to be later described. Inorder to permit drainage of fluid from the interior of upper bodyportion 10; the same may be provided with upper and lower vent ordrainage apertures 36 and 37. The mandrel 29 may be provided with aninterior bore 38 for flow of ushing iiuid therethrough and in order toprevent leakage of such flushing iluid there may be provided packingmeans in the form of a ring 39 in the joint between the lower end of themandrel 29 and the hammer member 34.

A piston rod 40 having a bore 41 extending therethrough is secured tothe hammer member 34 by screw threads or the like 42 and in order toprevent leakage of flushing liuid, there may be provided a packing ring43 in the joint between the piston rod 40 and the hammer member 34. Thepiston rod 40 extends through the intermediate body portion 14 andterminates within the lower body portion 19, as clearly shown in FIG.lc. The packing rings 16 at the upper end of the intermediate bodyportion 14 engage the outer surface of the piston rod 40` to provide apacking gland thereby preventing leakage of uid from within the chamber42 provided by the intermediate body portion 14 and adjacent the lowerend of the body portion 14 there may be provided packing means in theform of packing rings. 43y and 44 engaging the outer surface of thepiston rod 40 to prevent leakage of tluid from the chamber 42 in theintermediate body portion 14.

Slidably disposed within the chamber 42 of the intermediate body portion14 is a sleeve 4S and as best shown in FIGS. 2, 3 and 4, sleeve 45 isprovided at the lower end with longitudinally extending slots 46 in thewall portion thereof. At the lower end of the sleeve 45 and securedwithin the fingers 47 provided by the slots 4'6 by welding or the like,is a ring 48 which provides an inwardly extending liange, the purpose ofwhich will be presently described. The ring 48 is provided with a bore49 extending therethrough for freely receiving the piston rod 40 asclearly shown in FIG. 2. The intermediate wall section of the sleeve 45is provided with a smooth cylindrical inner surface 50 and such innersurface 50 merges into an upwardly and outwardly beveled section I51 atthe upper end of the sleeve 45, the purpose of which will be laterdescribed.

With particular reference to FIG. 2, it will be seen that the piston rod40 is provided with an integral an- 4 nular shoulder 52 which isdisposed on the piston rod 40 in such a manner as to be movabletherewith between the upper and lower ends of the chamber 42 in theintermediate body portion 14. While the annular shoulder '52 is shown asbeing integral with the piston rod 40, nevertheless, such annularshoulder may, if desired, be made separate from the piston rod 40 andsecured thereto in any suitable or desired manner. The upper surface 53of the annular shoulder 52 is beveled upwardly and outwardly and thesurface 53 serves to receive and support an upwardly opening cup washerl54. The cup washer 54 may be formed of brass or other metallic materialhaving similar and suitable properties and the washer 54 is providedwith a downwardly and inwardly extending flange portion 55 which engagesthe surface 53 on the annular shoulder 52 and the outer surface 56 ofthe washer 54 is substantialll cylindrical and engages the inner surface50 of the sleeve 45 to provide a sealing engagement therebetween. Theinner surface 57 of the upper portion of the washer 54 is flaredupwardly and outwardly in order to provide for limited deformation ofthe washer 54 by reason of the iluid pressure exerted against thesurface `57 to urge the outer surface 56 of the washer 54 intoengagement with the inner surface 5t) of the sleeve 45. 'Ihe Washer 54is secured in position on the piston rod 40 and in engagement with theupper surface 53 of the annular shoulder 52 by a retaining ring 58received on the piston rod 40 and engaging'the upper surface 59 of theilange 55 of the washer 54, as well as engaging a portion of the aredsurface 57 of the washer 54. The retaining ring `53 is held in place inengagement with the washer 54 by a snap ring 60 removably received in agroove 61 in the outer surface of the piston rod 40. Replacement of thewasher 54 may be accomplished merely by removing the snap ring 60 andthe retaining ring 58, after which a new washer 54 may be placed on thepiston rod 40 and clamped in position by replacing the retaining ring 58and the snap ring 60.

The cup washer 54 engages the inner surface 5t) of the sleeve 45 asdescribed above, and this engagement provides a seal, but as the fluidpressure builds up above the washer 54 as later described, the sealbetween the washer 54 and the sleeve 45 is partially suiiicient toprevent leakage of fluid from above the washer 54 to below the same and,therefore, even though an incompressible Huid is contained in thechamber 42 of the intermediate portion 14 above the washer 54, suchfluid under high pressure is permitted to bleed by the outer cylindricalsurface of the sleeve 45, i.e., between the outer cylindrical surface ofthe sleeve 45 and the inner cylindrical surface of the intermediateportion 14, to the lower portion of the chamber 42 in the intermediatebody portion 14. Since the washer 54 is formed of brass or other metalof similar properties and since the sleeve 45 engaged by the washer 54is of steel, wear is substantially restricted to the relatively softmaterial of the washer 54 and since such washer may be convenientlyreplaced, vthis structure materially reduces the cost of maintaining thehydraulic jar of this invention in operation and also operates tomaintain a relatively high eiiiciency.

In describing the operation of the hydraulic jar of this invention, itis to be assumed that a drill string or the like is attached to theenlarged portion 31 on the upper end of the mandrel 29 and that afishing tool or oth.,r device is attached to the threaded portion 24 onthe lower end of the coupling member 23 attached to the lower end of thelower body portion 19. It is also to be assumed that the chamber 42 ofthe intermediate body portion 14 is substantially filled with a suitablehydraulic fluid, such as motor oil or other fluid having similar andsuitable properties. With particular reference to FIGS. 7 to l0, thereis shown diagrammatically the sequence of operation during delivery ofan impact and as shown in FIG. 7, the annular shoulder 52, as well asthe cup washer 54 which together provide a piston- 62 and the sleeveaooaso 45 are disposed at the lower end of the chamber 42 in theintermediate body portion 14. lIn this position, of course, the hammermember 34 will also be disposed at the lower end of the upper bodyportion 10. An upward force is applied to the drill string connected tothe mandrel 29 which in turn will move the piston rod 40 and the piston62 carried thereby upwardly and the initial upward movement of thepiston 62 will be substantially unimpeded, due to the fact that thehydraulic fluid in the chamber 42 may ow through the slots 46 in thesleeve 45 to the lower side of the piston 42. However, upon the upperedge of the cup washer reaching the upper ends of the slot 46, flow ofhydraulic uid from above the piston 62 to below the same will be out olfand, consequently, a pressure will rapidly build up above the piston 62.Since the hydraulic uid in the chamber 42 of the intermediate bodyportion 14 is substantially incompressible, further upward movement ofthe piston 62 will be prevented, due to the fact that the cup washer 54provides a nearly perfect seal with the inner surface 50 of the sleeve45 and as a result, hydraulic Huid must slowly bleed or flow by thesleeve 45 to the lower part of the sleeve 45 and then through slots 46.This will permit relatively slow upward movement of the piston rod 40and piston 62, at which time energy is Vstored in the drill string abovethe hydraulic jar of this invention, such energy being proportional tothe pressure created above the piston 62. In FIG. 8, the piston 62 isshown substantially midway of the upward movement thereof in the sleeve45 and as soon as the washer 54 reaches the flared portion 51 in theupper end of the sleeve 45, the fluid above the piston 62 will flowaround such piston to the space below the same thereby rapidlydissipating the pressure in the chamber 42 above the piston 62 whichresults in a rapid upward movement of the piston rod 4t) and the piston62 to the position shown in FIG. l0. The hammer member 34 connected tothe piston rod 40 also moves rapidly upward upon release of pressure inthe chamber 42 above the piston 62 and as a result, the upper surface 35of the hammer member 34 engages the lower surface 26 of the reducedportion 25 in the upper end of the upper body portion with a substantialimpact, such impact being carried through the intermediate and lowerbody portions to the coupling member 23 and to the fishing tool or otherdevice connected thereto to be delivered to the object lodged in theWell bore. During this sequence of operations the sleeve 45 remains atthe lower end of the chamber 42 in the v intermediate body portion 14 byreason of the fluid pressure exerted on the upper end of the sleeve 45,as well as on the upper surface of the ange 48 at the lower end of thesleeve 45.

Since more than one impact is usually necessary to dislodge objectsjammed or lodged in a well bore, provision is made in the hydraulic jarof this invention for resetting of the same to deliver subsequentimpacts without delivering a downward impact which would tend to jam theobject more rmly in the well bore and with particular reference to FIGS.ll to 14, there is shown the sequence of operations during resetting ofthe jar for a subsequent upward impact. Upon completion of the upwardimpact stroke, the drill string and mandrel 29, as Well as the pistonrod 46 and piston 62 is moved downwardly and as shown in FIGS. l1 and12, the cup washer 54 will be guided into the sleeve 45 by the flaredportion 51 in the upper end thereof, which will prevent shearing ordamage to the cup washer 54 and also in the event the same has beenslightly distorted outwardly, the washer 54l will be returned to itsoriginal diameter by the flared surface 51 and as soon as the washer 54enters the cylindrical portion 50 of the sleeve 45 as shown in FIG. 12,fluid below the piston 42 will be placed under pressure and such fluidwill iiow through the slots 46 to the lower side of the flange 48 on thesleeve 45 which will result in exerting an upward pressure on suchllange 48 to cause the sleeve 45 to move upwardly as clearly shown inFIG. l2. This upward movement of the sleeve 45 results in enlarging thechamber below the piston 62 sufciently to accommodate the increase inpressure on the relatively incompressible fluid contained below thepiston 62. Further downward movement of the piston 62 and upwardmovement of the sleeve 45 will result in movement of the upper edge ofthe washer 54 below the upper ends of the slots 46, at which time fluidbelow the piston 42 will flow through the slots 46 and into the spaceabove the piston 62, after which the piston 62 may move downwardly untilthe lower end 63 thereof engages the flange 48 on the sleeve 45 whichwill result in moving the sleeve 45 downwardly to the lower end of thechamber 42 in the intermediate body portion 14, as clearly shown in FIG.14. The device is now in condition to Start the sequence of operationshown in FIGS. 7 to 10 to impart a further upward impact tending todislodge the object jammed in the well bore.

The use of a cup washer on the piston, yas above described, permits theuse of a hydraulic fluid which is relatively light and of low viscosity,such as motor oil or the like, which materially reduces the powerrequired to operate the device, since the amount of power is absorbed byheavy or high viscosity hydraulic fluids and furthermore, the use olf -acup washer of brass or other similar material substantially eliminateswear in other parts of ,the device, such wear being localized in thewasher which may be conveniently removed and replaced. The hydraulic jarof this invention may be operated to deliver relatively rapid upwardimpacts and reset without delivering 4a downward impact therebymaterially increasing the efficiency of the device and -resulting in therapid dislodgement 0f objects jammed in a well bore.

It will be obvious to those skilled in the art that various changes maybe made in the invention without departing from the spirit and scopethereof and therefore the -invention is not limited by that which isshown in the drawings and described in the specification, but only asindicated in the appended cla-ims.

What is claimed is:

l. A hydraulic jar comprising an upper elongated hollow body portion, anintermediate elongated hollow body portion removably secured to thelower end of said upper body portion, a lower elongated hollow bodyportion removably secured to the lower end of said intermediate bodyportion, a coupling member removably secured to the lower end of saidlower body portion, a reduced portion in'said upper body portionadjacent the upper end providing a downwardly `facing impact shoulder,said reduced portion having a non-circular -bore extending therethrough,an elongated mandrel slidably and non-rotatably received in said boreand terminating within said upper body portion, a coupling member on theupper end of said mandrel 'above said upper body portion, a hammermember secured to the lower end of said mandrel and slidable within saidupper body portion to engage said impact shoulder, a piston rod securedto said hammer member, said piston rod extending through saidintermediate body portion and terminating within said lower bodyportion, a sleeve of less length than said intermediate body portion,said sleeve being slidably dispo-sed in said intermediate body portion,an inwardly extending flange at the lower end of said sleeve, the lowerwall section of said sleeve having longitudinally disposed slotstherein, the intermediate wall section of said sleeve having -a smoothcylindrical inner surface, said inner surface merging into `a beveledsection at the upper end of said sleeve and la piston on said piston rodslidably received in said sleeve and movable between the lower Iandupper ends of said intermediate body portion, said piston cornprising anannular shoulder integr-ral with said piston rod, a yieldable, metallicupwardly opening cup washer received on said piston rod in engagementwith the upper surface of said annular shoulder, a retaining ringreceived on said rod and engaging the upper surface of said washer, agroove in said piston rod and a snap ring received in said groove andengaging said retaining ring to secure said lwasher in place, the uppersurface of said washer being flared upwardly and outwardly and the outersurface of said Washer engaging the cylindrical inner surface of saidsleeve during a portion of the upward movement of said piston to providea seal therewith while IPermitting a relatively slow -iluid ow aroundsaid sleeve from the upper to the lower side thereof.

2. A hydraulic jar comprising an upper elongated hollow body portion, anintermediate elongated hollow body portion removably secured to thelower end of said upper body portion, a lower elongated hollow bodyportion removably secured to the lower end of said intermediate bodyportion, a coupling member removably secured to the lower end of saidlower lbody portion, a reduced portion in said upper Ibody portionadjacent the upper end providing a downwardly facing impact shoulder,said reduced portion having a bore extending therethrough, an elongatedmandrel slidably and non-rotatably received in said bore and terminatingwithin said upper body portion, a coupling member on the upper end ofsaid mandrel above said upper body portion, a hammer member secured tothe lower end of said mandrel and slidable within said upper bodyportion to engage said impact shoulder, 'a piston rod secured to saidhammer member, said piston rod extending through said intermediate bodyportion and terminating within said lower body portion, a Asleeve ofless length than said intermediate body portion, said sleeve beingslidably disposed in said intermediate blody portion, an inwardlyextending flange at the lower end of said sleeve, the lower wall sectionof said sleeve having longitudinally disposed slots therein, theintermediate wall section of said sleeve having a smooth cylindricalinner surface, said inner `surface merging into a beveled section at theupper end of said sleeve and a piston on said .piston rod slidablyreceived in said sleeve and `movable between the lower and upper ends ofsaid intermediate body portion, said piston comprising an annularshoulder integral with said piston rod, a yieldable, metallic upwardlyopening cup washer received on said piston rod in engagement with theupper surface of said annular shoulder, a retaining r-ing received onsaid rod and engaging the upper surface of said washer, a groove in saidpiston rod and a snap ring received in said groove and engaging saidretaining ring to secure said washer 4in place, the upper surface ofsaid washer being flared upwardly and outwardly and the outer surface ofsaid washer engaging the cylindrical inner surface of said sleeve duringa portion of the Iupward movement of said piston to provide a sealtherewith while permitting a relatively slow flluid flow around saidsleeve from the upper to the lower side thereof.

3. A hydraulic jar comprising an upper elongated hollow body portion, anintermediate elongated hollow body portion removably secured to thelower end of said upper body portion, a lower elongated hollow bodyportion removably secured to the lower end of said intermediate bodyportion, a coupling member removably secured to the lower end of saidlower body portion, a reduced portion in said upper body portionadjacent the upper end providing a downwardly facing impact shoulder,said reduced portion having a bore extending therethrough, an elongatedmandrel slidably and non-rotatably received in said bore and terminatingin said upper body portion, a coupling member on the upper end of saidmandrel above said upper body portion, a hammer member secured to thelower end of said mandrel and slidable within said upper body portion toengage said impact shoulder, a piston rod secured to said hammer member,said piston extending through said intermediate body portion andterminating within said lower body portion, a sleeve of less length thansaid intermediate body portion, said sleeve being slidably disposed insaid intermediate body portion,

an inwardly extending flange at the lower end of said sleeve, the lowerwall section of said sleeve having longitudinally disposed slotstherein, the intermediate wall section of said Sleeve having a smoothcylindrical inner surface, said inner surface merging into a beveledsection at the upper end of said sleeve and a piston on said piston rodslidably received in said sleeve and movable between the lower and upperends of said intermediate body portion, said piston comprising anannular shoulder on said piston rod, a yicldable, metallic upwardlyopening cup washer received on said piston rod in engagement with theupper surface of said annular shoulder, a retaining ring received onsaid rod and engaging the upper surface of said washer, a groove in saidpiston rod and a snap ring received in said groove and engaging saidretaining ring to Secure said washer in place, the upper surface of saidwasher being flared upwardly and outwardly and the outer surface of saidwasher engaging the cylindrical inner surface of said sleeve during aportion of the upward movement of said piston to provide a sealtherewith while permitting a relatively slow fluid flow around saidsleeve from the upper to the lower side thereof.

4. A hydraulic jar comprising an upper elongated hollow body portion, anintermediate elongated hollow body portion removably secured to thelower end of said upper body portion, a lower elongated hollow bodyportion removably secured to the lower end of said intermediate bodyportion, a coupling member removably secured to the lower end of saidlower body portion, a reduced portion in said upper body portionadjacent the upper end providing a downwardly facing impact shoulder,said reduced portion having a bore extending therethrough, an elongatedmandrel slidably and non-rotatably received in said bore and terminatingwithin said upper body portion, a coupling member on the upper end ofsaid mandrel above said upper body portion, a hammer member secured tothe lower end of said mandrel and slidable within said upper bodyportion to engage said impact shoulder, a piston rod secured to saidhammer member, said piston rod extending through said intermediate bodyportion and terminating within said lower body portion, a sleeve of lesslength than said intermediate body portion, said sleeve being slidablydisposed in said intermediate body portion, an inwardly extending ilangeat the lower end of said sleeve, the lower wall section of said sleevehaving longitudinally disposed slots therein, the intermediate wallsection of said sleeve having a smooth cylindrical inner surface, saidinner surface merging into a beveled section at the upper end of saidsleeve and a piston on Said piston rod slidably received in said sleeveand movable between the lower and upper ends of said intermediate bodyportion, said piston comprising an annular shoulder on said piston rod,a yieldable, metallic upwardly opening cup washer received on saidpiston rod in engagement with the upper surface of said annularshoulder, a retaining ring received on said rod and engaging the uppersurface of said washer, means engaging said retaining ring and saidpiston rod to secure said washer in place, the upper Surface of saidwasher being flared upwardly and outwardly and the outer surface of saidwasher engaging the cylindrical inner surface of said sleeve during aportion of the upward movement of said piston to provide a sealtherewith while permitting a relatively slow uid flow around said sleevefrom the upper to the lower side thereof.

5. A hydraulic jar comprising an upper elongated' hollow body portion,an intermediate elongated hollow body portion removably secured to thelower end of said upper body portion, a lower elongated hollow bodyportion removably secured to the lower end of said intermediate bodyportion, a coupling member removably secured to the lower end of saidlower body portion, a reduced portion in said upper body portionadjacent the upper end providing a downwardly facing impact shoulder,said re- 9 duced portion having a bore extending therethrough, anelongated mandrel slidably and non-rotatably received in said bore andterminating within said upper body portion, a coupling member on theupper end of said mandrel above said upper body portion, a hammer membersecured to the lower end of said mandrel and slidable within said upperbody portion to engage said impact shoulder, a pison rod secured to saidhammer member, said piston rod extending through said intermediate bodyportion and terminating within said lower body portion, a sleeve of lesslength than said intermediate body portion, said sleeve being slidablydisposed in said intermediate body portion, an inwardly extending flangeat the lower end of said sleeve, the lower wall section of said sleevehaving longitudinally disposed slots therein, the intermediate Wallsection of said sleeve having a smooth cylindrical inner surface, saidinner surface merging into a beveled section at the upper end of saidsleeve and a piston on said piston rod slidably received in said sleeveand movable between the lower and upper ends of said intermediate bodypor-l tion, said piston comprising an annular shoulder on said pistonrod, a yieldable, metallic upwardly opening cup washer received on saidpiston rod in engagement with the upper surface of said annularshoulder, means to secure said washer in place on said annular shoulder,the upper surface of said washer being liared upwardly and outwardly andthe outer surface of said washer engaging the cylindrical inner surfaceof said sleeve during a portion of the upward movement of said piston toprovide a seal therewith while permitting a relatively slow fluid flowaround said sleeve from the upper to the lower side thereof.

6. A hydraulic jar comprising an upper elongated hollow body portion, anintermediate elongated hollow body portion removably secured to thelower end of said upper body portion, a lower elongated hollow bodyportion removably secured to the lower end of said intermediate bodyportion, a coupling member removably secured to the lower end of saidlower body portion, a reduced portion in said upper body portionadjacent the upper end providing a downwardly facing impact shoulder,said reduced portion having a bore extending therethrough, an elongatedmandrel slidably and non-rotatably received in said bore and terminatingwithin said upper body portion, a coupling member on the upper end ofsaid mandrel above said upper body portion, a hammer member secured tothe lower end of said mandrel and slidable within said upper bodyportion to engage said impact shoulder, a piston rod secured to saidhammer member, said piston rod extending through said intermediate bodyportion and terminating within said lower body portion, a sleeve of lesslength than said intermediate body portion, said sleeve being slidablydisposed in said intermediate said portion, an inwardly extending flangeat the lower end of said sleeve, the lower wall section of said sleevehaving longitudinally disposed slots therein, the intermediate wallsection of said sleeve having a smooth cylindrical inner surface, saidinner surface merging into a beveled section at the upper end of saidsleeve and a piston on said piston rod slidably received in said sleeveand movable between the lower and upper ends of said intermediate bodyportion, said piston comprising an annular shoulder on said piston rod,a yieldable, metallic upwardly opening cup washer received on saidpiston rod in engagement with the upper surface of said annular shoulderand means to secure said washer in place on said annular shoulder, theouter surface of said washer engaging the cylindrical inner surface ofsaid sleeve during a portion of the upward movement of said piston toprovide a seal therewith while permitting a relatively slow fluid llowaround said sleeve from the upper to the lower side thereof.

7. A hydraulic jar comprising an upper elongated holv low body portion,an intermediate elongated hollow body portion removably secured to thelower end of said upper body portion, a lower elongated hollow bodyportion removably secured to the lower end of said intermediate bodyportion, a coupling member removably secured to the lower end of saidlower body portion, a reduced portion in said upper body portionadjacent the upper end providing a downwardly facing impact shoulder,said reduced portion having a bore extending therethrough, an elongatedmandrel slidably Vand non-rotatably received in said bore andterminating within said upper body portion, a coupling member on theupper end of said mandrel above said upper body portion, a hammer membersecured to the lower end of said mandrel and slidable within said upperbody portion to engage said impact shoulder, a piston rod secured tosaid hammer member, said piston rod extending through said intermediatebody portion and terminating within said lower body portion, a sleeve ofless length than said intermediate portion, said sleeve being slidablydisposed in said intermediate body portion, an inwardly extending angeat the lower end of said sleeve, the lower wall section of said sleevehaving longitudinally disposed slots therein, the intermediate wallsection of said sleeve having a smooth cylindrical inner surface, saidinner merging into a beveled section at the upper end of said sleeve anda piston on said piston rod slidably received in said sleeve and movablebetween the lower and upper ends of said intermediate body portion, saidpiston comprising an annular shoulder on said piston rod, a yieldableupwardly opening cup washer received on said piston rod and inengagement with the upper surface of said annular shoulder and means tosecure said washer in place on said annular shoulder, the outer surfaceof said washer engaging the cylindrical inner surface of said sleeveduring a portion of the upward movement of said piston to provide a sealtherewith while permitting a relatively slow uid flow around said sleevefrom the upper to the lower side thereof.

8. In a hydraulic jar, a hydraulic chamber having an outer cylindricalwall, a piston rod extending through said chamber, a shoulder on saidpiston rod, a yieldable, metallic washer removably secured on said rodand against said shoulder, a hammer member connected to said piston rod,an impact member connected to said cylindrical wall, a sleeve mounted insaid hydraulic chamber, said sleeve being movable with respect to bothsaid cylindrical wall and said washer, the outer surface of said washerengaging the inner surface of said sleeve during a portion of the upwardmovement of said washer to provide a seal between said washer and saidsleeve.

References Cited in the le of this patent UNITED STATES PATENTS1,129,394 Hughes Feb. 23, 1915 1,647,505 Wigle Aug. 2, 1927 1,769,289Harrah et al. July l, 1930 2,645,459 Sutliif July 14, 1953 2,802,703Harrison Aug. 13, 1957

